Senate Majority Leader Harry Reid is threatening to change the filibuster rule to allow a majority to end a filibuster of presidential nominees waiting for a vote on senatorial confirmation. Under the existing rules, such confirmation votes can be filibustered, with cloture of the filibuster requiring 60 votes. A change in the Senate rules (like the change in the filibuster rule) can also be filibustered, and cloture here actually requires 67 votes.
There is a strong argument, however, that a majority of the Senate can change its rules, notwithstanding the Senate filibuster rule requiring 67 votes. I have argued (with John McGinnis) that the Constitution requires a majority of the Senate to be able to change the rules:
The third and constitutionally correct view is that the Senate can choose to retain the filibuster rule, but that a majority must be able to change it. The Senate can thereby exercise its full constitutional authority to fashion rules of procedure but past majorities of the Senate cannot put current majorities in a procedural straitjacket. Thus, a change in the filibuster rule by a majority is not a “nuclear” option but instead the constitutional option – the route contemplated by our founding document.
Of course, the Senate majority’s undoubted power to change the filibuster rule does not mean that doing so would be good policy.